IOMMU group causing server to hang before bios

[callumh45]

I have been playing around with unraid's virtualisation and have been trying to set up a pfsense instance for a firewall. I have just brought a 4 port nic on ebay( Dell H092P INTEL PRO/1000 VT QUAD-PORT PCI-E GIGABIT NETWORK CARD) and put into my server and it is stopping it from booting and flashed the cursor in the top left corner when I view it, after some playing aroun I have figured out that when I turn off iommu in the bios it works as it should, if it helps the cpu and motherbord I'm using are a fx6300 and m5a99xevo, is it something I'm doing or possibly my hardware.

if anyone has any idea what it could be could you shine some light on it for me.

thanks in advance.